A buffer circuit senses and amplifies an input signal to generate an output signal. An electronic device including a semiconductor device may operate by transmitting and receiving signals between internal components of the electronic device or between the electronic device and an external component. Signal transmission and reception may be more accurately performed through a buffer circuit. The buffer circuit may repeat an input signal or convert a swing amplitude of an input signal. With increased integration degree and decreased power consumption in electronic devices, the power supply voltage (i.e. voltage level) used in electronic devices has been continuously reduced. When power supply voltage is reduced, swing amplitude of signals transmitted between internal components of electronic devices or between electronic devices and external components is also reduced. Thus, waveforms of buffer circuit output signals are sensitive to variations in process, voltage and temperature (i.e., PVT), and the output signal may be easily distorted. Therefore, operational stability of the buffer circuit needs to be secured to accurately transmit and receive signals.
In general, the buffer circuits include a differential amplifying circuit. The differential amplifying circuit may compare an input signal with a reference signal and amplify the difference between the input signal and the reference signal.